1. Field of the Invention
The present invention relates to an image forming apparatus, an image forming system, and an image forming method.
2. Description of the Related Art
In the field of image forming apparatuses, locked print and hold print have been known widely as effective functions to prevent leakage of confidential information from a document that a printer has output in response to a print command received from a personal computer (PC) as a host. If the locked print is ON, after receiving the print command from the PC, the printer receives a password via a control panel from a user and performs user authentication with the password. The printer starts printing only if the user is authentic. If the hold print is ON, after issuing the print command via the PC, the user has to issue a command to start printing via the control panel.
If the locked print or the hold print is ON, the printer temporarily stores data to be printed (hereinafter, “print data”) in a storage unit, such as a hard disk drive (HDD), before outputting (printing) the print data. If the print data is present in the storage unit without being output, available capacity of the storage unit may become insufficient due to the print data such that the printer cannot execute a new print command by using the locked print function or the hold print function. Therefore, to execute the new print command, it is necessary to output or delete the print data from the storage unit.
To solve such problems, Japanese Patent Application Laid-open No. 2006-268542 discloses a printing system that properly manages protected print jobs stored in a server device. The printing system monitors the print jobs stored in the printer. If the printing system finds a print job that is stored in the printer for a predetermined period without printed out or if the amount of the print job stored in the printer exceeds a predetermined value, the printer sends a notice to a client device from which the print command is received or deletes the stored print job.
However, even if the printing system sends the notice to the client device, the user may not recognize the notice if the user is away from the client device. Moreover, even if the printing system sends the notice to the client device while the user is using the client device, the user may ignore the notice.